Researchers at Duke University tested the foam of more than 100 coaches.

They found over 40 percent contained chlorinated-tris - a chemical banned from children's pajamas in the 1970s because of health risks.

They also found other globally-banned chemicals in many of the samples. Experts say the flame-retardants seep out of the sofa and into household dust, which is then inhaled by homeowners.

Studies have shown the chemicals can disrupt hormone production and cause cancer.

Chemicals were found most often in sofas as recently-purchased as five years ago.

The American Chemistry Council says there is no data to suggest the levels of flame retardants found would cause human health problems.

Experts say manufacturers are not required to prove chemicals are safe before they use them, and the only way to know if your couch contains these flame retardants is to have the foam tested, which is very expensive.